A gorilla’s life cycle starts with a gestation period, which lasts about 8.5 months.
You can sometimes tell that a gorilla is pregnant by looking at her swollen knuckles. Female mountain gorillas usually give birth at night and at any time of the year.
During gorilla trekking in Uganda or Rwanda, you may see gorillas of all ages, from young to old. If you are lucky, you might even see a newborn gorilla.
Gorillas have a very low birth rate. A female gives birth every four to six years and is only fertile for 1–2 days in a month. After giving birth, she will not mate again until the baby is about 4–6 years old. In her lifetime, a female gorilla may have only 2 to 6 babies.
When a baby gorilla is born, it is called an infant. It feeds on the mother’s milk until it is 3 to 4 years old. Newborn gorillas weigh about 4 pounds and are very weak at birth. They start sitting and trying to walk at 3 to 4 months old.
The mother carries the infant in her arms until about 6 months, and after that, the baby clings to her back until it is 4 to 6 years old.
Sometimes, infant male gorillas are killed when the group gets a new leader or when the mother joins another group. This is usually done by a Silverback who fears the young males may grow and one day challenge him.
At the age of 4 to 8 years, the infant becomes a juvenile. Juvenile gorillas can now do many things on their own, but they are still not fully grown. At this stage, they may weigh about 60 to 70 kilograms.
Between 10 and 15 years of age, a gorilla is considered an adult. Males at this age are called blackbacks. Females mature earlier than males. Female gorillas stop growing taller and mostly just gain weight, but males continue growing.
When blackback males start growing a patch of gray hair on their backs, they become Silverbacks. This is the final stage of a male gorilla’s life cycle. At this point, they stop growing in size and weight.
The average lifespan of a gorilla is about 35 to 40 years.
